The pegboard in the hardware store wasn't invented till 1962.
When Maja walks to the neighbor's house to fetch Patrick, Stuart's mother says she promised to take them to the movies. Maja asked what's playing. Stuart's mother says 'Sleeping Beauty' (1959), which opened in wide release (other than premieres) 25 December 1959, and would not be exhibited during the time frame of this story.
A theatre marquee displays "North by Northwest" (1959) playing, which premiered 1 July 1959 in Chicago, 17 July 1959 in Los Angeles, and 6 August 1959 in New York. The end of the movie shows Maja, Lewis, and Patrick attending an Independence Day celebration (4 July). Unless the year is 1960, "North by Northwest" would not be exhibited.
The Weber kettle grill in the hardware shop window is a modern style with aluminum tripod legs with wheels.
Min. 10 in hardware store, on display panel are expose screwdrivers sets with green transparent plastic handle, definitely not something from 1950's.
Maja tells her husband that she spent two years at a concentration camp during the war. However, she visibly does not have the number tattoo on her arm, that the Nazis put on prisoners at the camps. Being Romani, Maja's number would also have started with the letter "Z" (identifying her as a Gypsy).